1. Field of the Invention
The present invention relates to a thermoplastic resin composition having a delustered or matte appearance, which is excellent in impact resitance, rigidity, anti-thermal deformation (stability against deformation by heat) and molding property.
2. Description of the Prior Art
ABS-type resins have been widely in use for various uses for their excellent impact resistance, thermal deformation resistance, molding property and fine surface lustre. Meanwhile, in the field of automobile upholstery, home electric appliances etc. there has been an increasing demand for parts with their surface delustered or made matte for a desired fine and quiet appearance, for a sense of high quality and for ensuring or improving safety through controlling reflection of light. For controlling luster and for making parts matte there are a number of conventional methods such as a method of improving the die's (mold's inside) surface, of coating with a delustering paint or mixing the resin with inorganic substances or rubbers. So far, however, no satisfactory results have been obtained by any of these methods. That is, improving the die's surface is accompanied by the difficulty of repairing and/or doing maintenance. Worse, the molded part's luster also depends on molding conditions, hence it is difficult to obtain molded parts constant in luster.
When an inorganic substance is added to a synthetic resin, this results in a marked drop of the resin's impact resistance, while addition of a rubber or rubbery matter causes lowering of rigidity, is likely to give rise to the so-called flow-mark or weld line, and after all it is difficult to obtain molded articles with excellent appearance. It is proposed to add to ABS resin copolymers of glycidyl methacrylate and ethylene, styrene, acrylonitrile ad acrylic ester etc. but even by this method lowering of impact resistance and molding property will result, also giving rise to color uneveness.